Spray nozzle assembly

ABSTRACT

A spray nozzle comprising a nozzle body ( 110 ) having an air channel in fluid communication with an air supply, and directing air to one or more air openings ( 160 ) at an end of the nozzle body, and a liquid channel in fluid communication with a liquid supply and directing a liquid to a liquid outlet ( 150 ) of the nozzle body. An air cap ( 120 ) is disposed at the end of the nozzle body and has an orifice in fluid communication with the one or more than one air openings, the orifice is disposed about the outside of the liquid outlet. The spray nozzle also comprises an extension ( 170 ) placed on the liquid outlet, outlet protrudes beyond the surface of the air cap. The spray nozzle is well suited for use under windy conditions in that fouling of the nozzle is reduced or eliminated.

FIELD OF THE INVENTION

The present invention relates to an externally atomizing spray nozzleassembly. More particularly, the present invention relates to anexternally atomizing spray nozzle assembly for dispensing liquids.

BACKGROUND OF THE INVENTION

The dispensing of liquids using a spray nozzle under windy conditionscan result in fouling and poor performance of the spray nozzle assemblyresulting in repeated down-time of equipment for cleaning. This isespecially true when polymeric or particulate-containing liquids orliquids comprising components that may agglomerate are sprayed underwindy conditions such as those found within aircraft-based spraypractices spraying herbicides, pesticides or fertilizers, spraying ofvolatile paints in well ventilated environments such as in automotiveassembly lines, traffic paint spraying or dispensing of liquidcompositions onto a track from a train.

Water-based friction modifiers from onboard a locomotive to the top of arail requires the use of a nozzle having a design that ensures that theproduct is applied consistently & reliably. In order to be acommercially feasible system, the dispensing nozzle must be fullyfunctioning between maintenance periods that can range between 90 and180 days. Unlike onboard dispensing systems that tout a liquid stream asa means of dispensing a lubricant to the top of a rail, an atomized formis preferred when a water-based friction modifier is used, as it permitsthe entire width of the rail to be covered, is applicable to a widerange of curves, and leads to faster drying rates.

However, with an atomized spray, environmental & physical conditions canadversely affect the spray pattern, which can lead to rapid build-up ofthe sprayed material on the surface of the nozzle. Environmentalconditions include cross flow conditions, for example, the impact ofentrained wind currents caused by the moving locomotive. The physicaldesign of the nozzle can also impact on the airflow by creating airturbulence or regions of negative pressure, which can cause the atomizedspray to circulate back to the nozzle where it is subsequentlydeposited. Such a build-up of material on the surface of the nozzle canimpede the flow of atomizing air from the nozzle, and reduce the flow ofproduct from the nozzle liquid orifice.

Standard air atomization nozzles use air caps having a pair ofdiametrically opposed air horns disposed at an acute angle (e.g. 45°),relative to the top surface of the air cap to flatten out a fluid streamemitted from the center of the cap. These air horns tend to clog due tooverspray, especially in the presence of external air currents. Suchclogging causes an imbalance in the air pressure at the front face ofthe nozzle, which results in a misdirected, partially atomized fluidstream.

U.S. Pat. No. 2,587,993 describes an externally mixing, air atomizationspray nozzle having a circular liquid orifice centrally disposed in thenozzle, an air outlet concentrically disposed and outside the liquidoutlet, and two pairs of diametrically opposed air outlets, each pairequally spaced from and outside of the air outlet. One of the pairs ofthe air outlets directing air flow inwardly of the air cap, and theother pair directing air flow substantially parallel with the air flowfrom emerging from the center of the cap. This spray nozzle produces aflat, fan-shaped spray pattern, surrounded by an air envelope. The airenvelope limits the amount of over spray of the liquid.

U.S. Pat. No. 4,236,674 describes an externally mixing, air atomizingliquid spray nozzle having an elliptical liquid outlet, and anelliptical air outlet concentrically disposed and outside the liquidoutlet. This nozzle design directly atomizes the liquid emitted from thespray nozzle into a flat, fan-shaped spray pattern, without the need ofadditional air horns to flatten out the atomised liquid spray emittedfrom the center of the nozzle.

It is an object of the invention to overcome disadvantages of the priorart.

The above object is met by the combinations of features of the mainclaims, the sub-claims disclose further advantageous embodiments of theinvention.

SUMMARY OF THE INVENTION

The present invention relates to an externally atomizing spray nozzleassembly. More particularly, the present invention relates to anexternally atomizing spray nozzle assembly for dispensing liquids.

According to one aspect of the present invention, there is provided aspray nozzle comprising:

a body having:

-   -   at least one air channel in fluid communication with an air        supply, the at least one air channel being adapted to direct air        to at least one air opening at a downstream end of the nozzle        body; and    -   a liquid channel in fluid communication with a liquid supply,        the liquid channel being adapted to direct a liquid to a liquid        opening at a downstream end of the nozzle body;

an air cap disposed at the downstream end of the nozzle body, the aircap having an orifice in fluid communication with the liquid opening andthe at least one air opening, the orifice disposed about the outside ofthe liquid opening, the air cap optionally having no air horns; and

an extension placed on the liquid outlet, so that the liquid outletprotrudes beyond an outside face surface of the air cap.

In this aspect, the orifice directs a flow of compressed air in aforward direction that is substantially parallel to a direction of flowof liquid emitted from the liquid opening to result in at least partialatomization of the liquid.

In an alternate embodiment, the air cap of the spray nozzle of thepresent invention further comprises a pair of air horns equally spacedfrom the center of the air cap and located outside of the orifice, eachair horn having an air outlet inclined at an angle of 45° with respectto the top surface of the air cap.

The nozzle of the present invention may further comprise an air purgecap for placement around the air cap, the air purge cap having anopening disposed about the outside of the air cap, wherein, the nozzlebody further comprises one or more than one ports in fluid communicationwith the air channel, the one, or more than one ports for directing aportion of the air from the air supply to an air conduit in fluidcommunication with the opening of the purge shroud. The air diverted tothe air conduit is emitted through the opening of the air purge captoward the center of the air cap, wherein the velocity of the airemitted from the opening is preferably lower than the velocity of theair emitted from the orifice.

In another embodiment, the spray nozzle of the present invention furthercomprises an air purge cap (shroud) placed around the air cap, the airpurge shroud having an opening disposed about the orifice of the aircap, the air purge cap directing air from a second air supply to an airconduit in fluid communication with the opening of the purge shroud.

The present invention also provides a spray nozzle comprising: bodyhaving:

-   -   at least one air channel in fluid communication with an air        supply, the at least one air channel being adapted to direct air        to at least one air opening at a downstream end of the nozzle        body; and    -   a liquid channel in fluid communication with a liquid supply,        the liquid channel being adapted to direct a liquid to a liquid        opening at a downstream end of the nozzle body; and

an air cap disposed at the downstream end of the nozzle body in fluidcommunication with the liquid opening and the at least one air opening,and having an orifice disposed about the outside of the liquid opening;

an air purge cap disposed around the air cap, the air purge cap havingan opening disposed about the outside of the air cap,

an extension placed on the liquid outlet, so that the liquid outletprotrudes beyond an outside face surface of the air cap,

wherein, the nozzle body further comprising one or more than one portsin fluid communication with the air channel, the one, or more than oneports for directing a portion of the air from the air supply to an airconduit in fluid communication with the opening of the purge shroud.

In this aspect of the present invention as just defined, the orificedirects a flow of compressed air in a forward direction that issubstantially parallel to a direction of flow of liquid emitted from theliquid opening to result in at least partial atomization of the liquid,and wherein the air purge cap diverts some of the air from the at leastone air channel to emit air through the opening and toward the center ofthe air cap, the air emitted from the opening being preferably of alower pressure than the air emitted from the orifice. The air purgeshroud directs air, preferably, exclusively, from a second air supply toan air conduit in fluid communication with the opening of the purgeshroud.

In an alternate embodiment of the invention, the orifice of the air capis circular, and is preferably concentrically disposed about the outsideof the liquid opening.

In another embodiment of the invention, the opening of the air purge capis circular, and is preferably concentrically disposed about the outsideof the air cap.

Alternatively the air cap further comprises a plurality of orifices,which are preferably arc-shaped, positioned in a circular arrangement,the plurality of orifices in fluid communication with the at least oneair opening, the arrangement disposed about the outside of the orificeof the air cap.

When the air cap comprises the above-described plurality of orifices,then the orifice of the air cap is preferably in fluid communicationwith only the liquid opening so that no air is emitted from the orificeof the air cap.

In another embodiment, the extension is a duckbill valve.

In another embodiment the extended portion of the liquid opening istapered at its end.

In another embodiment, the nozzle of the present invention is enclosedwithin a housing that has a port for allowing the atomized liquidproduced by the nozzle to be emitted outside of the housing.

In another embodiment, the housing comprises a sealing means, forexample, an O-ring, for forming a seal between the nozzle and the portof the housing.

The nozzle of the present invention produces an annular air flow fromthe central orifice that is substantially parallel to the flow of aliquid material emitted from the spray nozzle. This type of air flowresults in an atomized material that has a larger drop size than thatproduced using a spray nozzle having a pair of oppositely disposed sprayhorns, which are equally spaced from the center orifice of the air cap.The larger drop size of the atomized material produced according to thepresent invention results in a narrower spray pattern, with asignificantly reduced amount of overspray and buildup on the spraynozzle and cap.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent fromthe following description in which reference is made to the appendeddrawings wherein:

FIGS. 1A and 1B show sections of side elevational views of examples ofprior art spray nozzle assemblies.

FIGS. 2A and 2B show sections of side elevational views of examples ofembodiments of the spray nozzle assembly of the present invention.

FIG. 2C shows a front view of an air cap (air purge cap) used with anexample of an embodiment of the spray nozzle assembly of the presentinvention.

FIG. 3 shows a section of a side elevational view of an alternateexample of an embodiment of the spray nozzle assembly of the presentinvention, which includes an air purge cap.

FIG. 4 shows an front view of the of the nozzle assembly of FIG. 3, inthe direction of arrows 4-4.

FIG. 5A shows a section of a side elevational view of an example of anembodiment of the present invention, in which the nozzle assembly shownin FIG. 3 is partially enclosed within a rectangular housing.

FIG. 5B shows a bottom plan view of the example of FIG. 5A.

FIGS. 6A-B show pictures of the air cap portion of the spray nozzleassembly of FIG. 1A, partially enclosed within a rectangular housing,before and after 6.5 hours of spraying KELTRACK™ (a friction modifiercomposition) in the presence of a 30-31 km/hr. wind.

FIGS. 7A-B show pictures of the air cap portion of the spray nozzleassembly of FIGS. 3 and 4, partially enclosed within a rectangularhousing, before and after 8 hours of spraying KELTRACK™ (a frictionmodifier composition) in the presence of a 30 km/hr. wind.

FIG. 8 shows an example of an alternate housing for the spray nozzleassembly.

DESCRIPTION OF PREFERRED EMBODIMENT

The present invention relates to an externally atomizing spray nozzleassembly. More particularly, the present invention relates to anexternally atomizing spray nozzle assembly for dispensing liquids, forexample but not limited to friction modifiers or lubricants.

The following description is of a preferred embodiment by way of exampleonly and without limitation to the combination of features necessary forcarrying the invention into effect.

The spray nozzle assembly of the present invention is suited foratomising viscous liquids, or liquids comprising particulates, forexample but not limited to liquid friction control compositions to beapplied to the top of a rail of railway track. Non-limiting examples ofsuch liquid friction control compositions include KELTRACK™ and thosedisclosed in WO 98/13445, WO 02/26919, CA 2,321,507, or EP 02252651(which are incorporated herein by reference). However, it is to beunderstood that any liquid may be dispensed using the spray nozzleassembly as described herein.

The inventors have observed that existing spray nozzles (as shown inFIGS. 1A and B) are not suitable for delivery of viscous fluids, orfluids comprising particulates under windy conditions due to fouling ofthe spray nozzle. Windy conditions tend increase the rate of depositionof the atomized liquid on the spray nozzle. This problem is exasperatedunder conditions of continuous wind, for example those encounteredduring application of liquid friction control compositions to railwaytracks from a moving Hi-Rail truck or on board a train. However, otherconditions that produce cross flow air current may also lead to foulingof a spray nozzle. Fouling of spray nozzles may also occur withindifferent spray applications, for example but not limited toaircraft-based spraying of fertilizers, pesticides or herbicides,traffic line spraying, or paint spraying under well ventilatedconditions within assembly lines, and the nozzle assembly of thisinvention may be suited for these uses as well.

The spray nozzle assembly as described herein is also suited fordispensing an atomized spray under conditions with cross flow aircurrents that would otherwise result in the fouling of the spray nozzlefrom over spray. The spray nozzles of the present invention reduce oreliminate fouling when used under conditions having cross flow aircurrents. Without wishing to be bound by theory, the spray nozzles ofthe present invention reduce fouling of the nozzle by:

i) reducing the fanning of the atomized spray emerging from the spraynozzle, for example by either reducing or removing point sources oflaterally supplied air to the spray nozzle, for example, the lateral airsupply delivered through the air horns (e.g. 65, FIGS. 1A and 1B), or byremoving the air horns, and associate air supply from the spray nozzle(e.g. FIG. 2A);

ii) creating a positive pressure microenvironment at the front face ofthe spray nozzle, thereby increasing the velocity of air flow over thesurface of the nozzle face to reduce or eliminate deposition of spraydroplets on the nozzle face. Preferably the positive pressuremicroenvironment is uniform with respect to the atomized spray, in thatthis positive pressure microenvironment does not produce an asymmetricalover spray. The increase in the positive pressure microenvironment ofthe spray nozzle may be obtained by, for example, which is not to beconsidered limiting in any manner, supplying an air stream via a purgeshroud (also referred to as an air purge cap; e.g. FIG. 2C, and 230,FIG. 3);

iii) increasing the flow of air that is coaxial with the atomized spray,relative to any lateral air flow. This may be done using any suitablemeans, for example, but not limited to either:

-   -   a) extending the liquid outlet (150, FIGS. 2A and 2B) of the        spray nozzle beyond the front outside surface of air cap 120 or        200;    -   b) adding a duckbill (e.g. 170, FIGS. 2A, 2B, 3 and 4) to the        spray outlet; or    -   c) adding a housing that surrounds a portion of the spray nozzle        to reduce or remove external air currents from around the spray        nozzle (FIGS. 5A and 5B);

iv) or, a combination of the above.

Referring to FIG. 1A, there is shown a spray nozzle assembly (10) usingprior art air cap 20, liquid cap 50, and side-loading nozzle body 55.Air cap 20 has both a centrally-located circular orifice 30 and a pairof equally-spaced air outlets 40 and 45, inclined at an angle of 45°.Liquid emitted from liquid aperture 60 is atomized by the annular flowof air emitted from circular orifice 30. The atomized spray is thenflattened or fanned out by the air flow directed from the air outlets 40and 45 in air horns 64 and 65. An air-actuated needle valve 70 is usedto open and close liquid aperture 60.

FIG. 1B shows a rear-loading spray nozzle assembly (75), using theliquid cap and air cap of the nozzle assembly illustrated in FIG. 1A,and replacing the needle valve with a flexible duckbill 80, as is knownin the art. The duckbill may be made of rubber or other flexiblematerial. The base of duckbill 80 is secured between air cap 20 andliquid cap 50, and extends axially beyond the top face of air cap 20. Asthe front end of duckbill 80 occupies the entire area of air orifice 30,only liquid is emitted from the center of air cap 20. When used in windyconditions, or in situations where there are strong air currentsgenerated, for example, by ventilation systems, the air outlets and/orliquid outlet of both of the spray nozzle assemblies shown in FIGS. 1Aand 1B become easily coated due to overspray of the atomized liquid,resulting in increasingly degraded spray performance over time.

Referring to FIG. 2A, there is shown a non-limiting example of a spraynozzle assembly (100) of the present invention including a nozzle body110, an air cap 120, and a liquid cap 130. A fastening nut 125 is usedto secure air cap 120 to liquid cap 130. The liquid cap 130, may beintegral with the nozzle body 110. Nozzle body (110) comprises a more orless centrally disposed longitudinally extending channel 140 forcarrying the liquid. The liquid is directed to liquid outlet 150, whichis in fluid communication with a circular orifice 160 in air cap 120.The base of a flexible rubber duckbill 170 is secured between air cap120 and liquid cap 130. A retaining ring 180 having air holes 185 evenlydistributed about its perimeter is positioned between the base of theduckbill 170 and air cap 120 to secure the duckbill in position.

Air channel 190 provides compressed air in fluid communication withcircular orifice 160. Movement of a liquid from liquid chamber 140 bythe use of a pump results in a flow of a liquid through liquid outlet150 and through duckbill 170. Compressed air moving through air channels190 passes through holes 185 in retaining ring 180, and then throughcircular orifice 160 producing a uniform, circular, coaxial air flow,and atomizes the liquid emerging from the liquid outlet 150 to producean atomized spray.

In the non-limiting example shown in FIG. 2A, the uniform, circular,coaxial air flow that emerges from circular orifice 160, produces aspray pattern with reduced overspray thereby reducing fouling of thenozzle. Also the coaxial air flow helps to maintain the regionsurrounding the liquid outlet 150 free of deposited atomized liquid.

An alternate non-limiting example of the present invention is shown inFIG. 2B, where the air cap of the spray nozzle assembly depicted in FIG.2A is replaced with air cap 200 having both a centrally-located circularorifice 210 and a pair of air outlets (220, 225) equally spaced from thecenter of the air cap, and inclined at an angle of 45° with respect tothe top surface of the cap. The air emitted from the air outlets 220 and225 causes fanning of the atomized spray produced from the center of aircap 200.

In another aspect of the present invention, the length of the liquidoutlet 150 is extended beyond the front face of the air cap (120, 200),and may be tapered at its tip. In this example, the duckbill may be alsobe used to further extend the extended portion of the liquid outlet, bereplaced by an air- or mechanically actuated needle valve, or usedtogether with a needle valve.

In an additional example of the present invention illustrated in FIGS. 3and 4, the spray nozzle shown in FIG. 2A includes an air purge cap (orshroud) 230 located about air cap 120. Air purge cap 230 has one (e.g.FIG. 4) or more than one (e.g. see FIG. 2C) purge openings 240concentrically disposed about the outside of air cap 120. Air channel190 may be adapted to divert compressed air via one, or more than one,port 250 located within liquid cap (130) to air conduit 260 formedbetween liquid cap 130, air cap 120, and air purge cap 230 so that airis released through one, or more than one, purge opening 240. The sizeof port 250 may be adjusted to regulate the pressure and volume ofcompressed air flowing out through purge opening 240. For example, whichis not meant to be considered limiting in any manner, use of 2 ports(250) each of about 1.27 mm (0.05 inch) dia, and placed 180° apart, 3ports (250), each of about 0.794 mm (0.03125 inch) dia. and spacedequidistantly, about 120° apart around the liquid cap (130), or 5 ports(250), each of about 0.889 mm (0.035 inch) dia. and spaced 72° apart,may be sufficient to deliver airflow through the purge opening (240).However, additional ports (250), having alternated opening diameters maybe used as required.

The purge opening may comprise an annular continuous ring opening toprovide a uniform stream of air around the coaxial air flow providedthrough circular orifice 160, for example as shown in FIG. 4, however, aplurality of openings may also be employed to provide a positivepressure environment at the front face of the spray nozzle (see FIG.2C). For example, which is not to be considered limiting in any manner,several partial annular ring openings, or semi-circular openings may beused, or a plurality of either round or circular openings may bedisposed in a concentric manner in purge shroud 230, around circularorifice 160. The clearance of the purge opening (240) between the cornerof the air cap (120) and the inner edge of the purge air cap (230)should be chosen so that the velocity of the emitted air effectivelyprevents the deposition of material on the circular orifice 160, but atthe same time does not interfere with the direction of flow of theresulting atomized spray and result in overspray. The width of theclearance can be determined by routine experimentation without thenecessity of inventive ingenuity. Non-limiting examples of the width ofthe purge opening 240 include from about 0.254 mm to about 5.08 mm(about 0.010 inch to about 0.2 inch), from about 1.27 mm to about 3.81mm (0.05 inch to about 0.15 inch), about 1.54 mm to about 2.54 mm (about0.06 inch, or about 0.1 inch), about 2.54 mm (0.1 inch), or about 1.6 mm(0.063 inch).

In an alternative embodiment, air conduit 260 is supplied by anindependent source of pressurized air, so that the velocity and/orpressure of air emitted from purge opening 240 can be independentlycontrolled.

The air released from purge opening 240 produces a positive pressuremicroenvironment at the front face of the spray nozzle. Any suitable airpressure may be used that ensures reduced fouling arising from overspray. Preferably, the velocity and volume of air emerging from purgeopening 240 is less than that emerging from circular orifice 160. Morepreferably, the velocity of the air emerging from purge opening 240 isabout 0.05 to about 90%, more preferably about 0.1 to about 50% of thevelocity of the air that is released through circular orifice 160.

In another aspect of the present invention, the air emitted from purgeopening 240 is emitted at an angle of from about 0 to about 90°, morepreferably about 0 to about 45°, with respect to the top face of air cap120.

FIGS. 5A, 5B and 8, show non-limiting examples of housings that thespray nozzle assembly illustrated in FIG. 2A may be attached to when inuse in the field. In these examples, which are not to be consideredlimiting in any manner, the housing may be configured as a nozzle cover(270, FIGS. 5A and B) or as a recessed housing (290, FIG. 8). However,other housing configurations may also be contemplated that provide ameans for attaching the nozzle while in use in the field, protecting thenozzle components, or both.

With reference to FIGS. 5A and 5B, the nozzle cover (270) may compriseone, or more than one port 280 to permit the spray from the nozzleassembly to exit. Alternatively, a recessed housing (290; FIG. 8) may beused to provide ready access to nozzle components in the filed, yet dueto the recess within the housing, provide protection to the nozzlecomponents.

The housing may be separate from the nozzle assembly, or the housing maybe attached to the nozzle assembly for example, but not limited to,attached to the nozzle body, or the outer circumference of the purgeshroud. The housing may help ensure that the nozzle assembly is freefrom fouling. Even though the housing assists in reducing fouling of thenozzle assembly, the housing may not be required to reduce fouling ofthe air cap of the nozzle assembly.

The housing (270, FIGS. 5A and 5B; or 290, FIG. 8) also protects thenozzle assembly from grease, salt, ice-buildup, foreign debris and rocksduring use. The housing (270; 290) is therefore preferably constructedof a strong, resilient material that is resistant to corrosion. In thecase of a nozzle cover (270), the housing may be made in the form of arectangular box or a cylinder, however, any form may be used that caneffectively protect the spray nozzle assembly, and that does not impedeits continuous operation.

If the housing is a nozzle cover, and if the nozzle cover is not beattached to the nozzle body, a second port may be provided within thenozzle cover to permit introduction of a second air stream within thecover. Preferably, the nozzle cover is sealed to ensure that air flowsonly past the nozzle port. This second stream creates a positivepressure microenvironment within the nozzle cover thereby ensuring airflow out from the nozzle cover and nozzle, and reducing fouling of thenozzle from over spray. A similar effect is created by attached thenozzle cover to the purge shroud, in that a air stream emerging from thepurge shroud.

Testing using a nozzle cover (270; FIGS. 5A and B) demonstrates reducedfouling of the nozzle assembly (see Example 6). Similar testing of therecessed housing (290, FIG. 8) also demonstrates low fouling (spraybuildup) of the nozzle assembly (see example 7).

Preferably the nozzle is recessed within the nozzle cover (270) orrecessed with the recessed housing (290) so that the outer surface ofthe nozzle assembly does not protrude from the housing.

Although it is preferred that the material emitted from the liquidnozzle is completely atomized, partially atomized material is within thescope of the present invention.

The spray nozzle of the present invention is especially useful forspraying liquid material that is viscous, but may be used for any typeof material, present in any form. The spray nozzle of the presentinvention is particularly suited for use in conditions where thematerial is to be applied in a windy environment.

Although the spray nozzle assemblies of the present invention have beenparticularly described for use in applying viscous friction controlcompositions to railway tracks, these spray nozzles are equallyeffective in applying any type of composition in an environment in whichthere are strong air currents. Examples of such alternate sprayapplications include, but are not limited to spraying of crops withpesticides, traffic line spraying, and spray coating of automobiles instrongly ventilated environments.

The above description is not intended to limit the claimed invention inany manner, furthermore, the discussed combination of features might notbe absolutely necessary for the inventive solution.

The present invention will be further illustrated in the followingexamples. However it is to be understood that these examples are forillustrative purposes only, and should not be used to limit the scope ofthe present invention in any manner.

EXAMPLE 1 (COMPARATIVE)

Spray Test Using a Spray Nozzle Having Separate Atomizing and FanningAir Flows and Using a Needle Valve.

This test employed a spray nozzle assembly consisting of a spray body(Model 1/4 JAU), a fluid cap (Model 60100), and an air cap having acentrally-located circular orifice and a pair of oppositely disposed airhorns (Model 67228-45), all supplied by Industrial Spray Products(Wheaton, Ill.). Each air horn was equally spaced from the center of thecap and inclined at an angle of 45° with respect to the top surface ofthe cap. The circular orifice of the air cap was bored out to a diameterof 0.125″ (0.3 cm). The spray nozzle assembly is shown in FIG. 1A. Whenin use, the air cap of the spray nozzle produced both an atomizing airflow from its centrally-located circular orifice and a fanning air flowfrom the air horns. An air-actuated needle valve, positioned within theliquid chamber of the liquid cap, was used to turn on or turn off theflow of liquid emitted through the liquid cap. The spray nozzle wasencased in a nozzle cover (3.91 in.×2.74 in.×2.63 in.) having a circularopening with a diameter of 1.5 in. approximately centrally disposed atits bottom end. The flat portion of the air cap of the spray nozzleassembly was positioned 9 mm above the opening of the nozzle cover.

The spray nozzle assembly was placed in a wind tunnel (2 ft×2 ft×6 ft)behind a mock locomotive wheel (36 inch diameter). An electrical blower(Dry Eaze, Model F174, 5000 CFM) was used to supply an air flow of 30-31km/hr. past the locomotive wheel. An friction modifier composition(KELTRACK™, Kelsan Technologies Corp.) was supplied through the nozzlebody and emitted from the center of the air cap at a spray rate of 0.1L/mile at a train speed of 30 km/hr. An anemometer instrument (FisherScientific) was used to measure the air speed traveling past the wheeland spray assembly during the test.

The spray nozzle and cover were positioned approximately 22 inchesbehind the center of the wheel (in the direction of the wind) with thebottom of the nozzle cover 4 in. above the surface of the floor. Air wassupplied through the centrally-located air orifice and the pair of airhorns at an air pressure of 20 psi. The test was run for a period of 6.5hr.

Buildup on the nozzle cover and the spray nozzle was seen early on inthe test and continued, resulting in deterioration of the sprayuniformity and direction. Build up was great enough to entirely blockoff the air flow from the air horns and most of the atomizing air flowfrom the center of the air cap (FIGS. 6A-B). Large amounts of spraybuildup were also seen in the inside surfaces of the nozzle cover body.

EXAMPLE 2 (COMPARATIVE)

Spray test using a spray nozzle having only a fanning air flow and usinga duckbill valve.

This test employed a spray nozzle assembly consisting of a spray body(Model 1/4 JBC), a fluid cap (Model 60100), and an air cap having acentrally-located circular orifice and a pair of oppositely disposed airhorns (Model 67228-45), all supplied by Industrial Spray Products(Wheaton, Ill.). Each air horn was equally spaced from the center of thecap and inclined at an angle of 45° with respect to the top surface ofthe cap. The circular orifice of the air cap was bored out to a diameterof 0.153″. A flexible rubber duckbill (supplied from Lubriquip Inc.,Cleveland, Ohio) was attached to the liquid outlet of the fluid cap. Thebase of the duckbill was secured between the air cap and the liquid cap.The front end of the duckbill protruded out of the centrally-locatedcircular orifice of the air cap and occupied the entire area of theorifice, so that only liquid could be emitted from the center of the aircap. The spray nozzle assembly is shown in FIG. 1B.

The test was run as described in Example 1, with the followingmodifications: the test was run for 8 hours using a spray application of0.1 L/mile, at a train speed of 30 km/hr., a wind speed of 30 km/hr.,and an air pressure setting of 40 psi. After the test was complete,there was product buildup seen on the trailing edge (in the directionaway from the wind source) of the spray nozzle and outside of the spraynozzle cover. Spray buildup encompassed 100% of the spray cap andnozzle, and was also observed on the outer surface of the retainingnuts.

EXAMPLE 3

Spray test using a spray nozzle having only an annular atomizing airflow.

This test employed spray nozzle assembly, nozzle cover and wind tunnelset-up of Example 2, except that the air cap was replaced with onehaving only a centrally-located circular orifice having a diameter of0.173″. The base of the duckbill was secured between the air cap and theliquid cap. A retaining ring having four air holes evenly distributedabout its perimeter was positioned between the base of the duckbill andthe air cap to secure the duckbill in position. The holes in theretaining ring permitted air to pass through to the circular orifice ofthe air cap. The front end of the duckbill protruded out of thecentrally-located circular orifice of the air cap and an annular orifice(0.25 wide) formed around the periphery of the duckbill. The air flowemitted through the annular opening was substantially parallel to theflow of liquid emitted from the duckbill. The spray nozzle assembly isshown in FIG. 2A.

The test was run for ½ hour using a spray rate of 0.1 L/mile at a trainspeed of 30 km/hr., in a wind speed of 30 km/hr, and an air pressuresetting of 40 psi. After this test was completed, there was noappreciable buildup seen on the spray nozzle or on the outside of thespray nozzle cover.

EXAMPLE 4

Spray Test Using a Spray Nozzle Having Separate Atomizing and FanningAir Flows and Using a Duckbill Valve.

This test employed spray nozzle assembly, nozzle cover and wind tunnelset-up of Example 2, except that that the centrally located circularorifice of the air cap was enlarged to a diameter of 4.39 mm (0.173inch). The front end of the duckbill protruded out of thecentrally-located circular orifice of the air cap and an annular orifice(0.25 mm wide) formed around the periphery of the duckbill. The air flowemitted through the annular opening was substantially parallel to theflow of liquid emitted from the duckbill. The spray nozzle assembly isshown in FIG. 2B.

The test was run for 8 hour using a spray rate of 0.1 L/mile at a trainspeed of 30 km/hr. in a wind speed of 30 km/hr, and an air pressuresetting of 40 psi. After this test was completed, coverage of the aircap was about 20-30% of the amount of coverage observed from the resultsof Example 2, and the trailing side of the nozzle cover had a similararea of deposition, but only 30% as thick as the thickness observed fromthe results of Example 2.

EXAMPLE 5

Spray Test Using a Spray Nozzle Providing an Atomizing Air Flow From SixEvenly Spaced Circular Openings.

This test employed the spray nozzle assembly, nozzle cover and windtunnel set-up of Example 2, except that the air cap was replaced with acap having six circular openings (each having a diameter of 3/64″)provided in a circular arrangement, concentric with a centrally-locatedcircular orifice having a diameter of 3.89 mm (0.153 inch). The centerof each circular opening was 3.5 mm from the center of the air cap. Thebase of the duckbill was secured between the air cap and the liquid cap.The front end of the duckbill protruded out of the centrally-locatedcircular orifice of the air cap and occupied the entire area of theorifice, so that only liquid could be emitted from the center of the aircap. The air cap of the spray nozzle assembly is shown in FIG. 2C. Eachof the circular openings provided an air flow that was substantiallyparallel to the flow of liquid emitted from the duckbill.

The test was run for ½ hour using a spray rate of 0.1 L/mile at a trainspeed of 30 km/hr. in a wind speed of 30 km/hr, and an air pressuresetting of 40 psi. After this test was completed, there was noappreciable buildup seen on the spray nozzle, and a minimal amount onthe outside of the spray nozzle cover.

EXAMPLE 6

Spray Test Using a Spray Nozzle Having Both an Annular Atomizing AirFlow, and a Purging Air Flow.

This test employed the spray nozzle assembly of Example 3, and thenozzle cover and wind tunnel set-up of Example 4. In addition, the spraynozzle included an air purge cap having a circular aperture(diameter=17.5 mm), which was secured around the liquid cap (FIG. 3). Anannular aperture 1.6 mm wide was formed between the outer edge of theair cap and a flange formed on the outside face of the air purge cap.The liquid cap was modified to add ports for feeding pressurized airfrom its air channels to an air conduit formed between the liquid capand the air purge cap. The air in the air conduit was directed throughthe annular aperture inwardly across the face of the air cap.

The test was run for 8 hours using a spray application of 0.1 L/mile ata train speed of 30 km/hr, in a wind speed of 30 km/hr, and an airpressure setting=40 psi. After this test was completed, coverage of theair cap was about 10-15% of the amount of coverage observed from theresults of Example 1 (FIGS. 7A-B). A similar area of buildup wasobserved on the outside of the nozzle cover to that seen from theresults of Example 4, however, the thickness of the layer was reduced by50% of that observed in Example 4.

EXAMPLE 7

Spray Test Using a Spray Nozzle Having Both an Annular Atomizing AirFlow, and a Purging Air Flow With a Modified Design.

This test employed the spray nozzle assembly of Example 3, and thenozzle cover and wind tunnel set-up of Example 4. In addition, the spraynozzle included an air purge cap having a circular aperture(diameter=17.5 mm), which was secured around the liquid cap (FIG. 3). Anannular aperture 1.6 mm (0.063 inch) wide was formed between the outeredge of the air cap and a flange formed on the outside face of the airpurge cap. The liquid cap was modified to add 5 ports each of 0.889 mm(0.035 inch) dia. and spaced 72° apart for feeding pressurized air fromits air channels to an air conduit formed between the liquid cap and theair purge cap. The air in the air conduit was directed through theannular aperture inwardly across the face of the air cap.

The test was run as outlined in Example 6, with an addition testparameter so that the spray nozzle assembly was subjected to acceleratedvibration testing over a range of temperatures. Reduced nozzle cloggingwas observed with this nozzle assembly.

The same nozzle assembly was then tested in the field, attached behind alocomotive wheel with a recessed housing (FIG. 8) and used to supplyliquid friction control composition to track.

The test nozzle was inspected approximately 1 month after installation.At that time, the nozzle had 36.5 hours of spraying time. The spraynozzle, flexible duckbill and air cap components were free fromcontamination. After 95 hours of filed testing the surrounding area hada slight partial coating of fluid of negligible thickness, with noindication of buildup, the duckbill looked clean, and the nozzleperformed in a manner as initially installed.

All citations are herein incorporated by reference.

The present invention has been described with regard to preferredembodiments. However, it will be obvious to persons skilled in the artthat a number of variations and modifications can be made withoutdeparting from the scope of the invention as described herein.

1. A spray nozzle comprising: a nozzle body having an air channel influid communication with an air supply, the air channel directing air toone, or more than one, air openings at a downstream end of the nozzlebody; and a liquid channel in fluid communication with a liquid supply,the liquid channel directing a liquid to a liquid outlet at thedownstream end of the nozzle body; an air cap disposed at the downstreamend of the nozzle body, the air cap having an orifice in fluidcommunication with the one or more than one air openings, the orificedisposed about the outside of the liquid outlet; and an extension placedon the liquid outlet, so that the liquid outlet protrudes beyond anoutside face surface of the air cap.
 2. The spray nozzle of claim 1,wherein the air cap further comprises a pair of air horns equally spacedfrom the center of the air cap and located outside of the orifice, eachair horn having an air outlet inclined at an angle of 45° with respectto the top surface of the air cap.
 3. The spray nozzle of claim 1,further comprising: an air purge shroud placed around the air cap, theair purge shroud having an opening disposed about the orifice of the aircap, wherein, the nozzle body further comprising one or more than oneports in fluid communication with the air channel, the one, or more thanone ports for directing a portion of the air from the air supply to anair conduit in fluid communication with the opening of the purge shroud.4. The spray nozzle of claim 3, wherein the velocity of the air emittedfrom the opening of the purge shroud is less than the velocity of theair that is emitted from the orifice.
 5. The spray nozzle of claim 3,wherein the velocity of the air emitted from the opening of the purgeshroud is about 0.05 to about 90% of the velocity of the air that isemitted from the orifice.
 6. The spray nozzle of claim 3, wherein theair emitted from the opening of the purge shroud is emitted at an angleof from about 0 to about 90° with respect to the direction of spray ofthe liquid.
 7. The spray nozzle of claim 3, wherein the air emitted fromthe orifice is emitted at an angle of from 0 to 45° with respect to thedirection of spray of the liquid.
 8. The spray nozzle of claim 1,further comprising: an air purge shroud placed around the air cap, theair purge shroud having an opening disposed about the orifice of the aircap, the air purge cap directing air from a second air supply to an airconduit in fluid communication with the opening of the purge shroud. 9.The spray nozzle of claim 8, wherein the velocity of the air emittedfrom the opening of the purge shroud is less than the velocity of theair that is emitted from the orifice.
 10. The spray nozzle of claim 8,wherein the velocity of the air emitted from the opening of the purgeshroud is from about 0.05 to about 90% of the velocity of the air thatis emitted from the orifice.
 11. The spray nozzle of claim 8, whereinthe air emitted from the opening of the purge shroud is emitted at anangle of from about 0 to about 90° with respect to the direction ofspray of the liquid.
 12. The spray nozzle of claim 8, wherein the airemitted from the orifice is emitted at an angle of from 0 to 45° withrespect to the direction of spray of the liquid.
 13. The spray nozzle ofclaim 1, wherein the air cap further comprises a second, or a pluralityof second orifices positioned in a circumferential arrangement aroundthe orifice, the second or a plurality of second orifices in fluidcommunication with the air supply.
 14. The spray nozzle of claim 13,wherein the second, or a plurality of second orifices are arc-shaped.15. The spray nozzle of claim 13, wherein the second, or a plurality ofsecond orifices are round.
 16. The spray nozzle of claim 1, wherein theextension is tapered at its end.
 17. The spray nozzle of claim 9,wherein the extension is a duckbill valve.
 18. The spray nozzle of claim1, further comprising a valve member for sealing the liquid opening. 19.The spray nozzle of claim 18, wherein the valve member is an airactuatable needle.
 20. The spray nozzle of claim 1, which is enclosedwithin a housing, the housing comprising a port for allowing theatomized liquid to be emitted outside of the housing.
 21. The spraynozzle of claim 20, wherein the housing comprises a sealing means forforming a seal between the spray nozzle and the port of the housing. 22.A spray nozzle comprising: a nozzle body having: an air channel in fluidcommunication with an air supply, the air channel directing air to atleast one air opening at a downstream end of the nozzle body; and aliquid channel in fluid communication with a liquid supply, the liquidchannel directing a liquid to a liquid outlet at the downstream end ofthe nozzle body; a air cap disposed at the downstream end of the nozzlebody in fluid communication with the liquid outlet and the air opening,and having an orifice disposed about the outside of the liquid outlet;an extension placed on the liquid outlet, so that the liquid outletprotrudes beyond an outside face surface of the air cap. an air purgeshroud disposed around the air cap, the air purge shroud having anopening disposed about the orifice of the air cap, wherein, the nozzlebody further comprising one or more than one ports in fluidcommunication with the air channel, the one, or more than one ports fordirecting a portion of the air from the air supply to an air conduit influid communication with the opening of the purge shroud.
 23. The spraynozzle of claim 22, wherein the air purge shroud directs air from asecond air supply to an air conduit in fluid communication with theopening of the purge shroud.
 24. The spray nozzle of claim 23, whereinthe air is directed exclusively from the second air supply.
 25. Thespray nozzle of claim 22, wherein the velocity of the air emitted fromthe opening of the purge shroud is less than the velocity of the airthat is emitted from the orifice.
 26. The spray nozzle of claim 22,wherein the velocity of the air emitted from the opening of the purgeshroud is from about 0.05% to about 90% of the velocity of the air thatis emitted from the orifice.
 27. The spray nozzle of claim 22, whereinthe air emitted from the opening of the purge shroud is emitted at anangle of from about 0 to about 90° with respect to the direction ofspray of the liquid.
 28. The spray nozzle of claim 22, wherein the airemitted from the orifice is emitted at an angle of from 0 to 45° withrespect to the direction of spray of the liquid.
 29. The spray nozzle ofclaim 22, wherein the air cap further comprises a second, or a pluralityof second orifices positioned in a circumferential arrangement aroundthe orifice, the second or the plurality of second orifices in fluidcommunication with the air supply.
 30. The spray nozzle of claim 29,wherein the second, or the plurality of second orifices are arc-shaped.31. The spray nozzle of claim 29, wherein the second, or a plurality ofsecond orifices are round.
 32. The spray nozzle of claim 22, wherein theextension is tapered at its end.
 33. The spray nozzle of claim 22,wherein the extension is a duckbill valve.
 34. The spray nozzle of claim22, further comprising a valve member for sealing the liquid opening.35. The spray nozzle of claim 34, wherein the valve member is an airactuatable needle.
 36. The spray nozzle of claim 22, which is enclosedwithin a housing, the housing comprising a port for allowing theatomized liquid to be emitted outside of the housing.
 37. The spraynozzle of claim 36, wherein the housing comprises a sealing means forforming a seal between the spray nozzle and the port of the housing.